Two-way voice conversations between parties at different locations make use of techniques which process voice signals in real time. On the other hand, when data is to be transmitted back and forth between different locations, it is not necessary to use real-time processing techniques. In contradistinction, it normally is undesirable economically to process such signals in real time, and techniques often are employed which involve time delays which are not significant for data, but which are too large for voice processing.
On technique often used in transmission of two-way voice conversations in real time is known as time division multiplex (TDM). One technique often used in transmission of data which incorporates time delays too large for voice processing is known as packet switching, a form of statistical TDM.
For many purposes, it is advantageous economically to employ a communication system which can transmit voice conversations and/or data interchangeably. It is well known to those skilled in the art that packet switching techniques would have certain inherent advantages as compared to TDM techniques for processing voice signals if the time presently utilized in packet switching could be sufficiently reduced to approximate those utilized in real time processing.
The present invention is directed toward a system employing packet switching techniques wherein the time delays have been sufficiently reduced to permit data and voice signals to be processed interchangeably in a common communication system. To this end it is necessary to convert signals in TDM form to signals in packet form and vice versa. More particularly the present invention is directed toward a new type of signal transformation apparatus wherein TDM signals are transformed into packet signals and packet signals are transformed into TDM signals, both transformations taking place with suitably minimized delays.